a 1-year-old boy was attacked by an off-leash dog

1.1.1.1 .

n-1nn \dfrac {\ln \left ( n\right) -\ln \left ( n-1\right) } {n-\left ( n-1\right) } \left ( \ln n\right).

1+1=2 1 0 0

1 www.zhixue.com 2 .

.

2025-11-11

62332 161231123 1.

2011 1 .